New Zealand's premier swimmer produced a near personal best-time yet couldn't quite put New Zealand on the podium on day one of the swimming finals at the Commonwealth Games.

The North Shore swimmer was fourth in the women's 200 metre freestyle final in Glasgow today.

Gold went to Australia's Emma McKeon in one minute 55.57 seconds, ahead of England's Siobhan O'Connor (1:55.82) with Australia's Bronte Barratt third (1:56.62).

But Boyle's time of 1:57.00 was just 0.18s slower than when she qualified in third in the heats earlier in the day in a new national record time.

"I was so happy with that event today," Boyle said soon after.

"I wasn't ranked anywhere near the podium, so I'm so happy to improve that much in one day. Definitely doing a best time was a great feeling for me."

The 26-year-old will now fancy her chances of winning gold in the 400m and 800m freestyle events at the Games.

"I think it's cool having a race that's not the most important one on the first day," she said.

"I haven't had the chance to race the 200 at a pinnacle event since 2010, 2011, so it's nice to improve my time. I didn't really know what to expect coming in, so it's good to see that I have some speed left."

She has a day off tomorrow and will be part of the NZ women's 4x200m freestyle relay team on Saturday before her specialist individual events.

Kiwi men's 100m backstroker Corey Main also has a final to look forward to after two strong efforts on day one.

The US-based Main was second in his semifinal in a personal-best time of 54.28 seconds to qualify fifth for the next day's final.

"That was a good swim, a good time and a PB - so I'm happy with that," Main said.

The NZ women's 4x100m relay team of Samantha Lucie-Smith, Laura Quilter, Samantha Lee and Ellen Quirke missed out on a medal when fourth, but the smashed the previous best national record time by almost four seconds with a 3:43.83 effort. The winners, Australia, set a new world record of 3:30.98.

Lee was sixth in her 100m butterfly semifinal, also in a PB that was just off a national record.

The first final in the pool at the Games saw the host nation's Hannah Miley send the crowd into a frenzy with her come-from-behind triumph over England's Aimee Willmott in the women's 400m Individual Medley in a Commonwealth Games record time of 4:31.76.

Canada's Ryan Cochrane claimed gold in the men's 400m freestyle final, also timing his swim to perfection to haul in the favourite David McKeon of Australia.

But the biggest noise was reserved for a Scottish 1-2 finish in the men's 200m breaststroke final, when Ross Murdoch upset favourite and hometown hero Michael Jamieson, winning in a stunning time of 2:07.30 that was just off the world record.